This invention relates to solar heating apparatus, and more particularly to such apparatus and system that concentrates the solar energy, and automatically tracks the sun throughout its daylight path to achieve a high temperature heat transfer, and for controlling and maintaining the desired temperature of the stored liquid medium.
Solar water heaters have been employed for many years throughout the world. They can be classified generally in two categories, namely panel solar heaters, and concentrator solar heaters, depending on the temperature requirements of the particular installation. The concentrator type of solar heater, of which the present invention is an example, employs a parabolic or cylindrical heat collector to concentrate and focus the reflected solar energy for producing temperatures above 212.degree. F to be suitable for use in steam heating applications, air conditioning, refrigeration systems, power generation, as well as other suitable heating applications up to 500.degree. F.
In order to fully utilize a concentrator type of solar heater, it is desirable to track the sun, and accordingly, it is conventional to mount the reflecting surface for rotation about one or more axes. Examples of such construction is illustrated by U.S. Pat. Nos. 2,182,222 and 820,127.
However, neither of these patents nor the others in the art, disclose a suitable control means to enable the heat collector to be continuously and automatically guided and oriented in the most advantageous position with respect to the sun throughout its daylight travel. Nor does the art disclose the novel techniques for sensing and controlling the temperature of the stored liquid medium throughout the day.